PHILADELPHIA – Thirteen pitches into Kaz Ishii’s start last night, the Mets had to know they were in trouble.

That’s because 12 of those pitches were balls. And the other one was hit into left field for a single.

Ishii didn’t improve much from there, and not coincidentally, neither did the Mets’ chances for victory in Philly. They lost their second straight, 5-4 to the Phils, and Ishii’s arm and the Mets’ bats were the primary reasons why.

Ishii pitched terribly, surrendering five runs on six hits and six walks in just five innings. And once again, the Mets (6-7) continued to struggle at the plate, going scoreless through the first eight innings before a four-run ninth-inning rally fell short.

“I let the team down,” Ishii said.

Ishii had been shaky in his first start against the Reds and brilliant in his second outing against Houston. But last night was his poorest game so far, a combination of wildness and ineffectiveness that put the game out of reach almost immediately.

The Phillies’ leadoff man was Jimmy Rollins, and after Ishii threw his first pitch for a ball, Rollins singled to left on the next offering. That would be the last strike for awhile.

Struggling with his cutter, Ishii walked Placido Polanco on four straight pitches, then followed that up by walking Bobby Abreu on four more in a row to load the bases. He then went 3-0 on Pat Burrell, making it 11 straight out of the strike zone. Ugly.

“It’s almost like a record skipping,” manager Willie Randolph said. “It was almost the same identical pitch.”

Said Mike Piazza, who caught Ishii, “That’s a frustrating night. Usually we’re able to subtract off something and at least get a strike.”

Ishii came back to go 2-2 on Burrell before the scorching left fielder (NL-high 19 RBIs) pulled a grounder through the hole and into left for an RBI single. A Jason Michaels sac fly made it 2-0 after one.

The Phillies made it 4-0 in the third on Burrell’s solo shot to left and David Bell’s RBI double off the center field wall. Bell added another RBI double, this one to right, in the fifth.

“It was a little frustrating, obviously,” Ishii said of his early control problems. “But I know what to work on for the next outing I have.”

The five runs were more than enough of a cushion for Philly lefty Randy Wolf, who was terrific for eight shutout innings before getting touched for three runs in the ninth. Trailing 5-0 entering the final frame, the Mets made it close against Wolf and reliever Tim Worrell, thanks to Carlos Beltran’s RBI single and Cliff Floyd’s mammoth three-run homer.

The Mets’ recent hot streak had masked their offensive futility so far this season, and last night was further evidence, as they didn’t have a batter reach second base until Victor Diaz’s eighth-inning double. They’ve also scored only 49 runs in their 13 games (3.8 per outing) and hit only two homers in their last seven contests.

They also could use some help on the basepaths, considering that after Victor Diaz doubled in the eighth inning, he promptly forgot how many outs there were and broke for third on Miguel Cairo’s one-out pop to center. It was caught and Diaz, who was halfway home by then, was easily doubled off second.